I'll refrain from picking games i played in my youth alot and just pick some from my (somewhat) newer library. Games I played and replayed the last few years for me would be world of warcraft, Warhammer 40k: Dawn of War (and expansions) The elder scrolls: Oblivion and neverwinter nights I and II. And as of late I got back into the FPS genre again with the release of Team Fortress II. That game just pushes all the right buttons 
And then some console and handheld games like Grand Tourismo 3 and monsterhunter freedom series

And then some console and handheld games like Grand Tourismo 3 and monsterhunter freedom series